"The cage culture is growing rapidly and will soon overtake the wild and natural fish production in the lake," Nyamweya observed.
The situation is not welcome by the environmentalists who claim the trend in the lake is a threat to the lake's ecosystem and a possibility of losing important species. The scientists observed that the changing dynamics of Lake Victoria fisheries over the last decade have led to an altered ecosystem.
Michael Nyaguti, the chairman of Magnum Environment Network protested that many cages are installed in the lake without following regulations.
He said farmed fish do escape and interact with other fish in the wild resulting in the spread of diseases and parasites.
"All these may result in ecological simplicity, and decrease in genetic diversity (due to genetic dilution) and increased mortality of the wild stocks from diseases," he explained.
Adding that with all the risky factors in place, cages will end up overtaking the natural fish production which will alter the entire lake ecosystem.
KMFRI data shows that species like Tilapia have already shrunk by more than 50 per cent in the last decade but the resilient Nile perch shrunk by 23 percent.
In the last 50 years, Lake Victoria produced about 60,000 metric tonnes of Tilapia annually. Currently, however, it can barely produce 20,000 tonnes.
The bigger Nile Perch has been resilient because one Nile Perch can produce 17 million eggs compared to Tilapia's 300 eggs.
But still, Nile Perch was about 340,000 metric tonnes a decade ago, but its number has steadily dropped to about 200,000 metric tonnes.